Controlled precipitation and polarization properties of CuCl grains in alkali-borosilicate glass

Abstract

Controlling the valence states of transition metal ions in glass matrices is critical for tailoring optical functionalities, yet achieving precise redox balance remains challenging. This study introduces boron nitride (BN) as a novel redox modulator during the heat treatment of copper-doped alkali-borosilicate glass. By systematically investigating the effects of BN on copper ion valence states (quantified via X-ray photoelectron spectroscopy), microstructure evolution, and optical polarization properties, we demonstrate that BN significantly enhances the reduction of Cu²⁺ to Cu⁺, suppresses CuO precipitation, and promotes uniform CuCl grain formation. The BN-incorporated glass exhibits remarkable visible light transmittance (up to 74.68%, a 65% increase over BN-free samples) and an exceptional extinction ratio of 12.5 dB at 500 nm after stretching reduction. These findings provide a groundbreaking strategy for designing high-performance optical glass with tailored polarization and transparency, bridging the gap between material innovation and functional optical device applications.